Tarnish On Silver Coins?

Question

I have purchased a number of new mint silver coins over the past few years - silver eagles and Canadian maple leafs - and today I noticed that a few have started to tarnish, turning black in places, even though they appear to be sealed in their original mint plastic envelopes. What causes this? Does it effect the value? should I do anything about it? What is the best way to store these coins? They are currently in a safe - dry and dark.

Answer 1

Silver naturally tarnishes if exposed to the elements. Unlike most corrosion which is caused by oxide formation, silver tarnish is actually silver sulfide. It follows that the best way to prevent silver tarnish is to prevent it from coming into contact with anything that contains sulfur, such as rubber.

If these coins are in sealed envelopes, it's likely that there are traces of sulfur in the envelopes; many synthetic plastics contain traces of it. However, if the tarnish is minor, I wouldn't worry about it. If the seals on these coins are not airtight and they are in an area where there is air circulation, rapid tarnishing may be a sign that there is a source of sulfur in the area.

It's best to leave the coins alone. Although tarnish may negatively affect the value of coins, taking them out of their original packaging (especially if it's sealed) would be even more detrimental.

The last warning I have is: never remove tarnish for collectible items like coins. Tarnish can be easily removed chemically, but this often damages the coin, and it also exposes more of the surface to further corrosion, whereas the existing tarnish will provide some protection against further corrosion.

It's hard for me to say how much value would be negatively affected without seeing the coins, but 9 times out of 10 the safest thing to do is to leave the coins as-is. Any lost value is going to be less than what would be lost if you intervened somehow. When appraising or buying a coin, most collectors will not view tarnish very negatively--but if you have damaged a coin through cleaning, they will be more likely to devalue or reject your coin.

Answer 2

Silver Coin Tarnish

Answer 3

Silver always tarnishes. It's the effect of oxygen. Has nothing to do with exposure to light. There's nothing you can do about it.

I've read somewhere that polishing coins (with silver polish) will reduce their value. The fact that they're still in their mint envelopes proves they've never been circulated, so I wouldn't take them out and polish them.

Sounds like you're storing them perfectly. Can you manage to live with the tarnish ?